Ok, brewing an APA this weekend (Zombie Dust clone), and want to make sure I have decent water to start with before I start heating my HTL. For the record, I have been brewing all grain batches of red ales, IPAs and IIPAs for months with this water and have no reason to think, as of yet, that I will have a problem with a different style.

My water is horrible to say the least. So I use RO water from the supermarket. For my area it was suggested to me as the best and only option. That being said, for IPA/APA, I was told to just add one tsp of gypsum for extract or two teaspoons to HLT water for all grain. For 5g batches. Nothing more, nothing less.

You could brew with that water, but the alkalinity is high and that would require a very acidic grist like a porter or stout with crystal malts. Beside the alkalinity, none of the other ions are crazy high, but some are higher than I would prefer. Diluting the water to reduce the Na and Mg content is a consideration. That would also reduce the alkalinity.

Acidification is an alternative for neutralizing the alkalinity. That could bring the water the rest of the way to usefulness!

Your water does look a little hard, but if you've been having luck with it, it doesn't necessarily mean that anything needs changing. Do you normally check your mash pH? If you're getting that in the right ball park, then you're apparently able to overcome the hardness. If your pH is still a little high, you could just consider adding a little sour malt to bring it down a hair.

If you want to start with water additions, though, you could always add some Ca back, in the form of CaSO4 for your APA. That will increase your Ca levels a little which should help to keep the pH lower, and also increase your SO4 levels, which should help bring out the hops. Adding Ca to control pH isn't the greatest option since a lot depends on the mash environment, but if you're able to check your pH it will give you an idea of how well that worked. The other option would be to partially dilute with some RO water to decrease the hardness and add back enough CaCl and CaSO4 to keep your Ca levels above 50 (better for the yeast).